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Ionophore‐Based Biphasic Chemical Sensing in Droplet Microfluidics
Author(s) -
Wang Xuewei,
Sun Meng,
Ferguson Stephen A.,
Hoff J. Damon,
Qin Yu,
Bailey Ryan C.,
Meyerhoff Mark E.
Publication year - 2019
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201902960
Subject(s) - microfluidics , microscale chemistry , bodipy , reagent , nanotechnology , chemistry , aqueous solution , electrolyte , ionophore , fluorescence , chemical engineering , materials science , organic chemistry , electrode , mathematics education , mathematics , physics , quantum mechanics , engineering , calcium
Droplet microfluidics is an enabling platform for high‐throughput screens, single‐cell studies, low‐volume chemical diagnostics, and microscale material syntheses. Analytical methods for real‐time and in situ detection of chemicals in the droplets will benefit these applications, but they remain limited. Reported herein is a novel heterogeneous chemical sensing strategy based on functionalization of the oil phase with rationally combined sensing reagents. Sub‐nanoliter oil segments containing pH‐sensitive fluorophores, ionophores, and ion‐exchangers enable highly selective and rapid fluorescence detection of physiologically important electrolytes (K + , Na + , and Cl − ) and polyions (protamine) in sub‐nanoliter aqueous droplets. Electrolyte analysis in whole blood is demonstrated without suffering from optical interference from the sample matrix. Moreover, an oil phase doped with an aza‐BODIPY dye allows indication of H 2 O 2 in the aqueous droplets, exemplifying sensing of targets beyond ionic species.